In many fields of use, for example in the field of products for crop protection, in the case of active pharmaceutical ingredients, in the case of production of animal feeds and animal feed additives or in the foods industry, carrier materials are used in order, for example, to convert liquid or resinous active ingredients to a free-flowing and storage-stable form. To produce the solid formulations, liquid or meltable substances are in some cases applied to carrier materials together with auxiliaries (for example surfactants and disintegrants). In the case of solid substances, the carrier materials serve primarily as a filler, whereas they absorb the liquid in the case of liquid or low-melting substances. This should afford easily manageable, outwardly dry absorbates, which are then marketed either as a powder directly (WP, wettable powder) or, in further-processed form, as granules/extrudates (WG, water dispersible granules).
A significant requirement on the carrier material is a sufficiently high absorptivity, such that a minimum amount of carrier material need be used. By means of conventional processes, it is possible to produce up to 65% absorbates (based on a liquid density of 1.00 g/ml) with sufficient flowability.
A further requirement in addition to the high loading of the carrier material with active ingredient is that the absorbates have a good flowability and a minimum level of dusting in the course of transport, transfer and the production of the absorbates. To improve the flowability, it has therefore been proposed, for example in EP 0984772 B1 and EP 0966207 B1, to use microgranular precipitated silicas in approximately spherical form and with a mean particle size of more than 150 μm as the carrier material. The absorbates obtained in this way do have an improved flowability. However, the processing properties are not optimal, since, in the course of production of absorbates, especially at high loading with liquid, caked material in the mixers and delivery systems is frequently observed with these precipitated silicas, and reduces the yield and the product quality and in some cases has to be removed in a costly and inconvenient manner.
There is therefore still a high demand for inexpensive carrier materials which have good processibility and allow absorbates with high loading and good flowability to be produced.